Method for the extraction of lithium from an electric battery comprising solid metallic lithium

ABSTRACT

A method for the extraction of lithium from an assembly of at least one cell of an electric battery including solid metallic lithium, such as a Lithium-Metal-Polymer battery, the method having an extraction phase including the following steps:positioning the assembly in an orientation in which a first edge of the assembly from which extend(s) one or more negative electrode or electrodes is located below a second edge of the assembly, opposite the first edge, and from which extend(s) one or more positive electrode or electrodes; andheating the assembly to a treatment temperature greater than or equal to the melting temperature of the solid metallic lithium.An installation implementing such a method is also provided.

The present invention relates to a method for the extraction of lithiumfrom a battery comprising solid metallic lithium.

The field of the invention is the field of batteries based on solidmetallic lithium, and in particular Lithium-Metal-Polymer batteries, andeven more particularly the field of the recycling of these batteries.

STATE OF THE ART

Batteries based on solid metallic lithium are known, such as for exampleLithium-Metal-Polymer (LMP®) batteries. These batteries are usedincreasingly, for example in electric vehicles or in electrical chargingstations. Thus, the number of LMP® batteries has been increasingcontinuously for several years.

The lifetime of the LMP® batteries is not infinite and it appearsnecessary to recycle these batteries. Now, even at end-of-life, an LMP®battery still comprises solid metallic lithium, which can be reused inother batteries or in other fields, and the value of which is notinsignificant.

However, there is currently no technique making it possible tosatisfactorily recover the solid metallic lithium from a battery.

An aim of the present invention is to overcome this drawback.

Another aim of the invention is to propose a method for the recovery ofthe solid metallic lithium from an assembly of at least one electricalenergy storage cell.

Another aim of the invention is to propose a method for the recovery ofthe solid metallic lithium from an assembly of at least one electricalenergy storage cell, in a simple manner.

Another aim of the invention is to propose a method for the recovery ofthe solid metallic lithium from an assembly of at least one electricalenergy storage cell, in an efficient manner while limiting and managingthe effect of potential short-circuits during recycling.

DISCLOSURE OF THE INVENTION First Solution Proposed by the Invention

According to a first solution, the invention makes it possible toachieve at least one of these aims by a method for the extraction oflithium from an assembly of at least one cell of an electric batterycomprising solid metallic lithium, such as a Lithium-Metal-Polymerbattery, said method comprising an extraction phase comprising thefollowing steps:

positioning said assembly in an orientation in which a first edge ofsaid assembly from which extend(s) one or more negative electrode orelectrodes is located below a second edge of said assembly, oppositesaid first edge, and from which extend(s) one or more positive electrodeor electrodes.

heating said assembly to a temperature, called treatment temperature,greater than or equal to the melting temperature of said solid metalliclithium.

The method according to the invention proposes to recover the lithiumfrom a battery comprising solid lithium, by treating the cells composingsaid battery, individually or together.

In addition, the method according to the invention proposes to recoverthe metallic lithium, preferably solid, from an assembly of at least onecell the lithium of which is in the liquid state, by heating saidassembly of cell(s) to a treatment temperature greater than the meltingtemperature of the solid metallic lithium. Once molten, the metalliclithium is drained naturally from each cell, wholly or partially, underthe effect of the force of gravity.

Thus, the method according to the invention allows simple and not verycomplex recovery of the solid metallic lithium.

Moreover, the method according to the invention proposes a specificorientation for each cell, the latter having a minimum inclination, sothat the first edge from which the negative electrode extends is locatedbelow the level of the second edge, opposite the first edge, from whichthe positive electrode extends. Such an orientation of each cell makesit possible on the one hand to facilitate the flow of the molten lithiumout of the cell by gravity, and on the other hand to avoid a contactbetween the molten lithium and the positive electrode or the currentcollector of the positive electrode, such a contact being capable ofcausing an electrical short-circuit or an electric arc, such ashort-circuit being capable of causing a fire.

In the present application, by “electrical energy storage cell” is meantan assembly comprising, at least:

a negative electrode formed by, or comprising, a layer of solid metalliclithium;

a positive electrode,

a solid electrolyte, in particular comprising lithium salt, arrangedbetween the positive electrode and the negative electrode, and

a current collector on the side of the positive electrode.

In the present application, the “solid metallic lithium” can comprise:

pure metallic lithium; or

a combination of at least one metallic lithium alloy; or

a combination of pure metallic lithium and at least one metallic lithiumalloy.

When the “solid metallic lithium” comprises a combination of differentforms of lithium, such as those indicated above, having differentmelting temperatures, then the heating step carries out heating theassembly of cell(s) to a treatment temperature greater than or equal to:

the lowest of said different melting temperatures; and

preferentially, the highest of said different melting temperatures.

According to a non-limitative embodiment example, the treatmenttemperature is greater than or equal to 180.5° C.

According to an embodiment example, the treatment temperature is lessthan or equal to a maximum temperature, for example of 300° C.

The assembly can comprise one single or only cell.

The assembly can comprise several cells assembled, or in particularstacked, in an assembly direction. The assembly direction can beperpendicular to the plane formed by each cell.

In particular, the assembly can correspond to a battery in which thecells are connected in series.

According to a preferred embodiment, the positioning step can carry outa vertical positioning of the assembly of cell(s), in which the firstedge is located downwards.

Thus, the gravitational flow of the molten lithium out of each cell isimproved.

In addition, the risk of contact between the molten lithium and thepositive electrode or electrodes is reduced, or zero.

Preferentially, the step of heating the assembly of cell(s) can becarried out under inert gas.

Thus, the method according to the invention reduces the risks ofaccidents, in particular, fire risks.

In addition, the method according to the invention makes it possible toavoid the formation of polluting compounds that may be generated byunwanted or uncontrolled physico-chemical reactions during theextraction of the lithium.

According to a non-limitative example, the inert gas can be, orcomprise, any one of the following gases: helium (He), neon (Ne), argon(Ar), krypton (Kr), xenon (Xe) and radon (Rn).

According to another embodiment, the step of heating the assembly ofcell(s) can be carried out under vacuum.

According to a particularly advantageous characteristic, the methodaccording to the invention can also comprise, before the extractionphase, a step of electrical charging of the assembly of cell(s), saidextraction phase being applied to said charged assembly.

The fact of electrically charging the cell or cells, and of carrying outthe extraction phase on the electrically charged cells, makes itpossible to increase the lithium extraction yield. In fact, theelectrical charging of a cell makes it possible to displace the lithiumions towards the negative electrode, which allows the recoverablequantity of lithium to be increased.

Each cell can be charged individually, or by electrical charging of theassembly of cell(s).

According to a particularly advantageous embodiment, the extractionphase can also comprise a step of compressing the assembly of cell(s).

Thus, the molten lithium is forced to drain out of each cell, whichincreases the quantity of lithium recovered.

The compression step can be carried out continuously, throughout theextraction phase. In this case, each cell is subjected to a compression,partially or wholly, throughout the entire duration of the extractionphase.

Alternatively, the compression step can be carried out separately, onceor several times, during the extraction phase. In this case, theextraction phase includes moments when the assembly of cell(s) is notsubjected to a compression.

Advantageously, the compression step can apply a compression to thesurface of the assembly of cell(s) by sweeping the surface of saidassembly from the second edge to the first edge. Thus, the moltenlithium is conveyed/guided progressively towards the first edge fromwhich extend(s) one or more negative electrode or electrodes, whichincreases the quantity of lithium recovered and reduces the risk ofcontact between the lithium and the positive electrode or electrodes.

For example, the compression step can be carried out by passing theassembly of cell(s) between two rollers.

According to another example, the compression step can be carried out bya compression roller compressing the assembly of cell(s) against abearing surface.

The compression can be applied by successive passes, each pass sweepingthe surface of the assembly of cell(s), starting from the second edge tothe first edge.

The gap between the compression rollers, respectively between thecompression roller and the bearing surface, can correspond to thethickness of the assembly of cell(s) minus the thickness of the solidmetallic lithium layer or layers. This makes it possible to apply acompression, while solid lithium still remains in the cell(s) assembly.

The gap between the two compression rollers, or respectively between thecompression roller and the bearing surface, can be reduced withsuccessive passes, so as to still apply a compression on the assembly ofcell(s).

The speed of passage between the compression rollers, respectively ofthe compression roller, and more generally the sweeping speed, can becomprised between a few mm and a few tens of mm per second.

Moreover, the method according to the invention can comprise, before theextraction phase, a step of removing at least one electrical connector,also known as a “crimp connector”, from at least one cell.

This makes it possible to facilitate the treatment of the assembly ofcell(s).

Moreover, the method according to the invention can comprise, before theextraction phase, a step of removing excess material at the level of atleast one, and particularly each, edge of the assembly of cell(s).

According to another aspect of the same invention, an installation isproposed for the extraction of lithium from an assembly of at least onecell of an electric battery comprising solid metallic lithium, such as aLithium-Metal-Polymer battery, said installation comprising:

a means for positioning said assembly in an orientation in which a firstedge of said assembly from which extend(s) one or more negativeelectrode(s) is located below a second edge of said assembly, oppositesaid first edge, and from which extend(s) one or more positive electrodeor electrodes; and

a heating means configured for heating said assembly to a treatmenttemperature greater than or equal to the melting temperature of saidsolid metallic lithium.

Generally, the installation comprises means configured to implement anycombination of at least one of the characteristics described above,which for the sake of brevity are not described in detail herein.

In particular, the heating means can comprise an oven.

Advantageously, the oven can be filled with an inert gas, or be placedunder vacuum.

The installation according to the invention can also comprise a meansfor compressing the assembly of cell(s).

The compression means can comprise at least one roller.

In particular, the compression means can comprise a single rollercompressing the assembly of cell(s) against a bearing surface. Thebearing surface can be heated to accelerate the temperature increase ofthe assembly of cell(s).

Alternatively, the compression means can comprise two rollers betweenwhich the assembly of cell(s) is passed.

Generally, the compression means can be configured to apply a continuouscompression throughout the extraction phase.

Alternatively, the compression means can be configured to apply acompression discontinuously over time, once or several times, during theextraction phase. In this case, the extraction phase includes momentswhen the assembly of cell(s) is not subjected to a compression.

Advantageously, the compression step can be configured to apply acompression, with a constant or variable value, progressively or bysweeping over the surface of the assembly of cell(s), from the secondedge to the first edge. Thus, the molten lithium is conveyed/guidedprogressively towards the first edge located in low position, whichincreases the quantity of lithium recovered and reduces the risk ofcontact between the lithium and the positive electrode or electrodes.

In the case of use of one or two compression rollers, then thecompression can be applied to the assembly of cells by successivepasses. Each pass applies a compression by sweeping over the surface ofthe assembly of cell(s), from the second edge to the first edge. At theend of each pass, the compression can be stopped, by withdrawing therollers or by withdrawing the roller from the bearing surface, to returnto the second edge in order to start a fresh pass.

The distance between the rollers, respectively between the compressionroller and the bearing surface, can be reduced with successive passes,in particular between two successive passes.

The method according to the invention can be implemented to treatseveral assemblies of cell(s), in particular several assemblies of cellsforming a battery pack and connected together in parallel within saidbattery pack.

At least two assemblies of cell(s) can be aligned side by side, withoutoverlapping, for example in a direction parallel to the first edge.

In this case, the compression can be applied to at least two assembliesof cell(s) by one and the same compression means, namely a set ofrollers, or one roller cooperating with a bearing surface.

Second Solution Proposed by the Invention

According to a second solution, the invention makes it possible toachieve at least one of these aims by a method for the extraction oflithium from an assembly of at least one cell of an electric batterycomprising solid metallic lithium, such as a Lithium-Metal-Polymerbattery, said method comprising an extraction phase comprising thefollowing steps:

positioning said assembly in an orientation in which a first edge ofsaid assembly from which extend(s) one or more negative electrodes islocated above a second edge of said assembly, opposite said first edge,and from which extend(s) one or more positive electrode or electrodes.

a step of immersion of the assembly of cell(s) in a liquid that isdenser than the liquid lithium and electrically insulating; and

heating said assembly to a temperature, called treatment temperature,greater than or equal to the melting temperature of said solid metalliclithium.

The method according to the invention proposes to recover the lithiumfrom a battery comprising lithium, by treating the cells composing saidbattery, individually or together.

In addition, the method according to the invention proposes to recoverthe metallic lithium from an assembly of at least one cell the lithiumof which is brought to the liquid state, by heating said assembly ofcell(s) to a treatment temperature greater than the melting temperatureof the solid metallic lithium. Once molten, the metallic lithium drainsnaturally from each cell under the effect of the difference in density.Thus, the method according to the invention allows simple and not verycomplex recovery of the solid metallic lithium.

Moreover, the method according to the invention proposes a specificorientation for each cell, the latter having a minimum inclination, sothat the first edge from which the negative electrode extends is locatedabove the level of the second edge, opposite the first edge, from whichthe positive electrode extends. Such an orientation of each cell makesit possible on the one hand to facilitate the flow of the molten lithiumout of the cell by difference in density, and on the other hand to avoida contact between the molten lithium and the positive electrode or thecurrent collector of the positive electrode, such a contact beingcapable of causing an electrical short-circuit, such a short-circuitbeing capable of causing a fire. In addition, immersion of the assemblyof cell(s) in a liquid makes it possible to improve the dissipation ofcalories from the cell, in particular during a short-circuit, and thusto significantly limit the effect thereof.

In the present application, by “electrical energy storage cell” is meantan assembly comprising, at least:

a negative electrode formed by, or comprising, a layer of solid metalliclithium;

a positive electrode,

a solid electrolyte, in particular comprising lithium salt, arrangedbetween the positive electrode and the negative electrode, and

a current collector on the side of the positive electrode.

In the present application, by “density” is meant the ratio between themass density of the liquid in question and the mass density of water.

In the present application, “solid metallic lithium” can comprise:

pure metallic lithium; or

a combination of at least one metallic lithium alloy; or

a combination of pure metallic lithium and at least one metallic lithiumalloy.

When the “solid metallic lithium” comprises a combination of differentforms of lithium, such as those indicated above, having differentmelting temperatures, then the heating step carries out heating theassembly of cell(s) to a treatment temperature greater than or equal to:

the lowest of said different melting temperatures; or preferentially,the highest of said different melting temperatures, or

a combination of the different temperatures, for example, or through atemperature gradient that extends from the first edge to the secondedge.

According to a non-limitative embodiment example, the treatmenttemperature, in the case of utilization of pure metallic lithium, isgreater than or equal to 180.5° C.

According to an embodiment example, the treatment temperature is lessthan or equal to a maximum temperature, for example of 300° C.

The assembly can comprise one single or only cell.

The assembly can comprise several cells assembled, or in particularstacked, in an assembly direction. The assembly direction can beperpendicular to the plane formed by each cell.

In particular, the assembly can correspond to a battery in which thecells are connected in series.

According to a preferred embodiment, the positioning step can carry outa vertical positioning of the assembly of cell(s), in which the firstedge is located upwards.

Thus, the flow of the molten lithium out of each cell, by difference indensity, is improved.

In addition, the risk of contact between the molten lithium and thepositive electrode or electrodes is reduced, or zero.

Preferentially, the immersion step is carried out by immersing theassembly of cell(s) completely in the liquid.

Thus, the method according to the invention reduces the risks ofaccidents, in particular, fire risks. In addition, the method accordingto the invention makes it possible to avoid the formation of pollutingcompounds that may be generated by unwanted or uncontrolledphysico-chemical reactions during the extraction of the lithium, inparticular by controlling the treatment temperature and the density ofthe liquid so that only the lithium or the lithium alloy can beextracted.

According to a particularly advantageous characteristic, the methodaccording to the invention can also comprise, before the extractionphase, a step of electrical charging of the assembly of cell(s), saidextraction phase being applied to said charged assembly.

The fact of electrically charging the cell or cells, and of carrying outthe extraction phase on the electrically charged cells, makes itpossible to increase the lithium extraction yield. In fact, theelectrical charging of a cell makes it possible to displace the lithiumions towards the negative electrode, which allows the recoverablequantity of lithium to be increased.

Each cell can be charged individually, or by electrical charging of theassembly of cell(s).

According to a particularly advantageous embodiment, the extractionphase can also comprise a step of compressing the assembly of cell(s).

Thus, the molten lithium is forced to drain out of each cell, whichincreases the quantity of lithium recovered and the kinetics of theprocess.

The compression step can be carried out continuously, throughout theextraction phase. In this case, each cell is subjected to a compression,partially or wholly, throughout the entire duration of the extractionphase.

Alternatively, the compression step can be carried out separately, onceor several times, during the extraction phase. In this case, theextraction phase includes moments in which the assembly of cell(s) isnot subjected to a compression.

Advantageously, the compression step can apply a compression to thesurface of the assembly of cell(s) by sweeping the surface of saidassembly from the second edge to the first edge. Thus, the moltenlithium is conveyed/guided progressively towards the first edge fromwhich extend(s) one or more negative electrodes, which increases thequantity of lithium recovered and reduces the risk of contact betweenthe lithium or lithium alloy and the positive electrode or electrodes.

For example, the compression step can be carried out by passing theassembly of cell(s) between two rollers.

According to another example, the compression step can be carried out bya compression roller compressing the assembly of cell(s) against abearing surface.

The compression step can be applied by successive passes, each passsweeping the surface of the assembly of cell(s), starting from thesecond edge to the first edge.

The gap between the compression rollers, respectively between thecompression roller and the bearing surface, can correspond to thethickness of the assembly of cell(s) minus the thickness of the solidmetallic lithium layer or layers. This makes it possible to apply acompression, while solid lithium still remains in the assembly ofcell(s).

The gap between the two compression rollers, respectively between thecompression roller and the bearing surface, also called platen, can bereduced with successive passes, so as to still apply a compression onthe assembly of cell(s).

The speed of passage between the compression rollers, or respectively ofthe compression roller cooperating with a platen, and more generally thesweeping speed, can be comprised between a few mm and a few tens of mmper second.

Moreover, the method according to the invention can comprise, before theextraction phase, a step of removing at least one electrical connector,also known as a “crimp connector”, from the cell.

This makes it possible to facilitate the treatment of the assembly ofcell(s).

Moreover, the method according to the invention can comprise, before theextraction phase, a step of removing excess material at the level of atleast one, and particularly each, edge of the assembly of cell(s).

According to another aspect of the same invention, an installation isproposed for the extraction of lithium from an assembly of at least oneelectric battery cell comprising solid metallic lithium, such as aLithium-Metal-Polymer battery, said installation comprising:

a means for positioning said assembly in an orientation in which a firstedge of said assembly from which extend(s) one or more negativeelectrode or electrodes is located above a second edge of said assembly,opposite said first edge, and from which extend(s) one or more positiveelectrode or electrodes;

an oven filled with a liquid that is denser than the liquid lithium andelectrically insulating; and

a heating means configured for heating said assembly to a treatmenttemperature greater than or equal to the melting temperature of saidsolid metallic lithium.

Generally, the installation comprises means configured to implement anycombination of at least one of the characteristics described above,which for the sake of brevity are not described in detail herein.

The liquid can be a natural or synthetic oil, comprising the followingphysico-chemical properties:

hydrophobic and non-reactive with respect to the lithium,

electrically insulating,

having a density greater than that of the lithium,

thermally stable beyond the melting temperature of the lithium, i.e.180.5° C.,

a flash point, as well as a self-ignition point, as high as possible.

The installation according to the invention can also comprise a meansfor compressing the assembly of cell(s).

The compression means can comprise at least one roller.

In particular, the compression means can comprise a single rollercompressing the assembly of cell(s) against a bearing surface. Thebearing surface can be heated to accelerate the temperature increase ofthe assembly of cell(s).

Alternatively, the compression means can comprise two rollers betweenwhich the assembly of cell(s) is passed.

Generally, the compression step can be configured to apply a continuouscompression throughout the extraction phase.

Alternatively, the compression means can be configured to apply acompression discontinuously over time, once or several times, during theextraction phase. In this case, the extraction phase includes momentswhen the assembly of cell(s) is not subjected to a compression.

Advantageously, the compression means can be configured to apply acompression, with a constant or variable value, progressively or bysweeping over the surface of the assembly of cell(s), from the secondedge to the first edge. Thus, the molten lithium is conveyed/guidedprogressively towards the first edge located in low position, whichincreases the quantity of lithium recovered and reduces the risk ofcontact between the lithium and the positive electrode or electrodes.

In the case of use of one or two compression rollers, then thecompression can be applied on the assembly of cells by successivepasses. Each pass applies a compression by sweeping over the surface ofthe assembly of cell(s), from the second edge to the first edge. At theend of each pass, the compression can be stopped, by withdrawing therollers or by withdrawing the roller from the bearing surface, to returnto the second edge in order to start a fresh pass.

The distance between the rollers, respectively between the compressionroller and the bearing surface, can be reduced with successive passes,and in particular between two successive passes.

The method according to the invention can be implemented to treatseveral assemblies of cell(s), in particular several assemblies of cellsforming a battery pack and connected together in parallel within saidbattery pack.

At least two assemblies of cell(s) can be aligned side by side, withoutoverlapping, for example in a direction parallel to the first edge.

In this case, the compression can be applied to at least two assembliesof cell(s) by one and the same compression means, namely a set ofrollers, or one roller cooperating with a bearing surface.

DESCRIPTION OF THE FIGURES AND EMBODIMENTS

Other advantages and characteristics will become apparent on examinationof the detailed description of embodiments which are in no waylimitative, and from the attached drawings in which:

FIG. 1 is a diagrammatic representation of a non-limitative embodimentexample of a cell within the meaning of the present invention;

FIG. 2 is a diagrammatic representation of a non-limitative embodimentexample of an assembly of cells within the meaning of the presentinvention;

FIG. 3 is a diagrammatic representation of a first non-limitativeembodiment example of a method according to the invention, conforming tothe first solution proposed;

FIG. 4 is a diagrammatic representation of a second non-limitativeembodiment example of a method according to the invention, conforming tothe first solution proposed; and

FIG. 5 is a diagrammatic representation of a non-limitative embodimentexample of an installation according to the invention, conforming to thefirst solution proposed;

FIG. 6 is a diagrammatic representation of a first non-limitativeembodiment example of a method according to the invention, conforming tothe second solution proposed;

FIG. 7 is a diagrammatic representation of a second non-limitativeembodiment example of a method according to the invention, conforming tothe second solution proposed;

FIG. 8 is a diagrammatic representation of a non-limitative embodimentexample of an installation according to the invention, conforming to thesecond solution proposed.

It is well understood that the embodiments that will be describedhereinafter are in no way limitative. Variants of the invention can beenvisaged comprising only a selection of the characteristics describedhereinafter, in isolation from the other characteristics described, ifthis selection of characteristics is sufficient to confer a technicaladvantage or to differentiate the invention with respect to the state ofthe prior art. This selection comprises at least one, preferablyfunctional, characteristic without structural details, or with only apart of the structural details if this part alone is sufficient toconfer a technical advantage or to differentiate the invention withrespect to the state of the prior art.

In the figures, elements common to several figures retain the samereference.

In the present application, by “density” is meant the ratio between themass density of the liquid in question and the mass density of water.

The liquid can be a natural or synthetic oil, comprising the followingphysico-chemical properties:

hydrophobic and non-reactive with respect to lithium,

electrically insulating,

having a density greater than that of lithium,

thermally stable beyond the melting temperature of lithium, i.e. 180.5°C.,

a flash point, as well as a self-ignition point, as high as possible.

FIG. 1 is a diagrammatic representation of a non-limitative embodimentexample of a cell within the meaning of the present invention,regardless of which of the two proposed solutions is implemented.

The cell 100, shown in FIG. 1, comprises a negative electrode 102 formedby, or comprising, a layer of solid metallic lithium.

The cell 100 also comprises a positive electrode 104. The positiveelectrode 104 is generally formed by a layer of composite based onpolymer and active material.

A layer 106 of solid electrolyte is arranged between the negativeelectrode 102 and the positive electrode 104. This layer of solidelectrolyte 106 can for example comprise lithium salt.

The cell 100 also comprises a current collector 108 on the side of thepositive electrode 104. The current collector 108 is generally producedfrom aluminium.

Conventionally, the negative electrode 102 of the cell 100 extendsbeyond the other elements of the cell 100 on the side of a first edge110 of the cell 100, here to the right of the figure; and the positiveelectrode 104 and/or the collector 108 of the cell 100 (said collector108 is connected to the positive electrode 104) extend(s) beyond theother elements of the cell 100 on the side of a second edge 112,opposite the first edge 110. In the example shown, only the collector108 extends beyond the assembly 100 on the second edge 112 thereof, hereto the left of the figure. In other examples, the extension may involveonly the positive electrode 104, or also the positive electrode 104 andthe collector 108.

Of course, the cell 100 shown in FIG. 1 is a very simplified version ofrealization, given by way of non-limitative illustration. The cellwithin the meaning of the present invention can comprise layers otherthan those indicated, or more layers, or layers the composition of whichis different from the composition given here by way of non-limitativeexample.

FIG. 2 is a diagrammatic representation of a non-limitative embodimentexample of an assembly of cell(s) within the meaning of the presentinvention, regardless of which of the two proposed solutions isimplemented.

The cell assembly 200, shown in FIG. 2, comprises one or more cellswithin the meaning of the present invention.

In particular, the cell assembly 200 comprises several identical cells100 ₁-100 _(n), assembled in a direction 202 perpendicular to the planeof the layers of each cell 100 _(i).

Each cell 100, may be identical to the cell 100 in FIG. 1.

In addition, between two adjacent cells 100 _(i)-100 _(i+1), with i<n,are arranged a positive electrode 204 _(i) and a current collector 206_(i) which is connected thereto.

Embodiment Examples according to the First Solution Proposed

FIG. 3 is a diagrammatic representation of a first non-limitativeembodiment example of a method according to the invention, conforming tothe first solution proposed;

The method 300, shown in FIG. 3, comprises a first, optional, step 302during which the electrical connectors, and in particular the currentconcentrators, also known as “crimp connectors”, of the assembly ofcell(s) are removed.

During an optional step 304, excess material, in particular solidmetallic lithium, at the level of each side edge of the assembly ofcell(s) is removed.

Then, the method 300 comprises a phase 306 of extraction of the metalliclithium from the cells.

The extraction phase 306 comprises a step 308 of positioning theassembly of cell(s) in an orientation in which the first edge from whichextend(s) the negative electrode or electrodes is located at a lowerlevel than the second edge from which extend(s) the positive electrodeor electrodes and the collectors. In particular, the step 308 positionsthe assembly of cell(s) in a vertical orientation, i.e. parallel to thegravity vector, with the edge from which extend(s) the negativeelectrode or electrodes, downwards. Preferentially, but in no waylimitatively, the assembly of cell(s) is held in this orientationthroughout the entire extraction phase 306.

The extraction phase 306 also comprises a step 310 of heating theassembly of cell(s) to a treatment temperature greater than or equal tothe melting temperature of the solid metallic lithium present in theassembly of cell(s), for example a temperature of 180.5° C. Thistemperature will cause the melting of the solid metallic lithium andextraction thereof from each cell by natural drainage under the effectof gravity. Preferentially, but in no way limitatively, the assembly ofcell(s) is maintained at this temperature throughout the entireextraction phase 306.

Advantageously, the heating step is carried out in a closed enclosurefilled with inert gas.

The extraction phase 306 can also comprise an optional step 312 ofcompressing the assembly of cell(s) so as to flush the molten lithiumout of each cell. The compression can be carried out continuously overall or part of the extraction phase 306. Alternatively, the compressionstep 312 can be reiterated discontinuously, several times during theextraction phase 306. Preferentially, the compression step 312 carriesout an application of the compression, progressively or by sweeping overthe surface of the assembly of cell(s), starting from the second edgefrom which extend(s) the positive electrode or electrodes and movingtowards the first edge from which extend(s) the negative electrode orelectrodes.

FIG. 4 is a diagrammatic representation of another non-limitativeembodiment example of a method according to the invention, conforming tothe first solution proposed.

The method 400, shown in FIG. 4, comprises all the steps of the method300 in FIG. 3.

The method 400 also comprises, prior to the steps of the method 300, astep 402 carrying out an electrical recharging of the treated cell(s).

Each cell can be partially or totally recharged.

The fact of electrically charging each cell makes it possible toincrease the quantity of lithium available for extraction, as theelectrical recharging causes migration of the lithium ions to thenegative electrode of the cell.

FIG. 5 is a diagrammatic representation of a non-limitative embodimentexample of an installation according to the invention, conforming to thefirst solution proposed.

The installation 500, shown in FIG. 5, can be used to implement themethod according to the invention, and in particular the methods 300 and400 in FIGS. 3 and 4.

The installation 500 makes it possible to extract and recover a part orall of the lithium from a battery cell comprising solid metalliclithium, such as for example the cell 100 in FIG. 1, or from an assemblyof cells such as the assembly 200 in FIG. 2.

The installation 500 comprises an oven 502, filled with an inert gas orplaced under vacuum, configured to heat the cell to a treatmenttemperature greater than or equal to the melting temperature of thesolid metallic lithium present in the cells, for example 180.5° C. or181° C.

The installation 500 comprises a pair of jaws 504 for holding the cell100, or the cell assembly 200, in a vertical, or at least inclined,position in which the first edge 110 is positioned below the level ofthe second edge 112. Each jaw 504 is mounted mobile on a vertical rail506 so as to displace the cell, or the assembly of cells 200,vertically.

The installation 500 also comprises a pair of rollers 508, havingbetween them a gap corresponding to the thickness of the cell 100, or ofthe assembly of cells 200, minus the thickness of the solid layer(s) ofmetallic lithium. The pair of rollers is positioned so that when thejaws 504 are displaced upwards, the cell 100, respectively the assemblyof cell(s) 200, passes between the rollers 508, starting from the secondedge 112. Thus, the rollers apply a compression to the cell 100,respectively to the cell assembly 200 progressively, starting from thesecond edge 112 and moving towards the first edge 110.

The installation also comprises a receptacle 510 for recovering themolten metallic lithium which flows out of each cell under the effect ofgravity. The receptacle 510 must be inert with respect to lithium.

Embodiment Examples according to the Second Solution Proposed

FIG. 6 is a diagrammatic representation of a non-limitative embodimentexample of a method according to the invention, conforming to the secondsolution proposed;

The method 600, shown in FIG. 6, comprises a first, optional, step 602during which the electrical connectors, also known as “crimpconnectors”, of each battery cell are removed.

During an optional step 604, excess material at the level of each sideedge of the assembly of cells is removed.

Then, the method 600 comprises a phase 606 of extraction of the metalliclithium from the cells.

The extraction phase 606 comprises a step 608 of positioning theassembly of cell(s) in an orientation in which the first edge 110 fromwhich extend(s) the negative electrode or electrodes 102 is located at ahigher level, in a vertical direction, than the second edge 112 fromwhich extend(s) the positive electrode or electrodes 104 and thecollectors. In particular, the step 608 positions the assembly ofcell(s) in a vertical orientation, i.e. parallel to the gravity vector,with the edge from which extend(s) the negative electrode or electrodes102, upwards. Preferentially, but in no way limitatively, the assemblyof cell(s) is held in this orientation throughout the entire extractionphase 606.

The extraction phase 606 comprises a step 609 of immersion of theassembly of cell(s) in a liquid 850 (see FIG. 8). For example in theembodiment shown in FIG. 8, the liquid 850 is a natural or syntheticoil, for example a paraffin oil, comprising the followingphysico-chemical properties:

hydrophobic and non-reactive with respect to lithium,

electrically insulating,

having a density greater than that of lithium,

thermally stable beyond the melting temperature of lithium, i.e. 180.5°C., and

a flash point, as well as a self-ignition point, as high as possible,for example a temperature greater than 600° C., and as a minimum greaterthan the treatment temperature of the cell.

The immersion step 609 is carried out by immersing the assembly ofcell(s) 200 in the liquid 850 so that the liquid 850 completely coversthe assembly of cell(s) 200.

This immersion step 609 is particularly advantageous for promotingsignificant heat exchange between the cell and the liquid 850, whichlimits the risks of overheating of the cell and the evacuation of thecalories generated during a short-circuit and improves the heatingkinetics.

The extraction phase 606 also comprises a step 610 of heating theassembly of cell(s) to a treatment temperature greater than or equal tothe melting temperature of the solid metallic lithium present in theassembly of cell(s), for example a temperature of 180.5° C. In theembodiment presented, the liquid 850 is heated by the oven, andtransfers heat to the assembly of cell(s). Once greater than the meltingtemperature of lithium, the temperature causes the melting of the solidmetallic lithium and extraction thereof from each cell by naturaldrainage under the effect of gravity. Preferentially, but in no waylimitatively, the assembly of cell(s) is maintained at this temperaturethroughout the entire extraction phase 606. The treatment temperaturemust not exceed a degradation temperature of the liquid 850, specific toeach liquid 850, beyond which the liquid 850 degrades. In other words,the liquid 850, when exceeding a threshold temperature, would changeproperties so that the aforementioned properties are no longer met.Ideally, the degradation temperature of the liquid must be greater than+40° C. (and for example between +60° C. and +60° C.) with respect tothe melting temperature of lithium.

Thus the method for the extraction of lithium from a battery makes itpossible to limit the effects of short-circuit electrical potentials bymaking the lithium flow via the first edge 110 from which extend(s) thenegative electrode or electrodes 102, and to control short-circuits byimmersing the assembly of cell(s) in a liquid that does not react withlithium and improving the dissipation of calories from the assembly ofcell(s), in particular during a short-circuit.

The extraction phase 606 can also comprise an optional step 612 ofcompressing the assembly of cell(s) so as to accelerate the extractionof the molten lithium out of each cell. The compression can be carriedout continuously over all or part of the extraction phase 606.Alternatively, the compression step 612 can be reiterateddiscontinuously, several times during the extraction phase 606.Preferentially, the compression step 612 carries out an application ofthe compression, progressively or by sweeping over the surface of theassembly of cell(s), starting from the second edge 112 from whichextend(s) the positive electrode or electrodes 104 and moving towardsthe first edge 110 from which extend(s) the negative electrode orelectrodes 102.

FIG. 7 is a diagrammatic representation of another non-limitativeembodiment example of a method according to the invention, conforming tothe second solution proposed;

The method 700, shown in FIG. 7, comprises all the steps of the method600 in FIG. 6.

The method 700 also comprises, prior to the steps of the method 600, astep 702 carrying out an electrical recharging of the treated cell orcells.

Each cell can be partially or totally recharged.

The fact of electrically charging each cell makes it possible toincrease the quantity of lithium available for extraction, as theelectrical recharging causes migration of the lithium ions to thenegative electrode of the cell, which improves the quantity of lithiumextracted as well as the kinetics of the operation.

FIG. 8 is a diagrammatic representation of a non-limitative embodimentexample of an installation according to the invention, conforming to thesecond solution proposed.

The installation 800, shown in FIG. 8, can be used to implement themethod according to the invention, and in particular the methods 600 and700 in FIGS. 6 and 7.

The installation 800 makes it possible to extract and recover a part orall of the lithium from a battery cell comprising solid metalliclithium, such as for example the cell 100 in FIG. 1, or from an assemblyof cells such as the assembly 200 in FIG. 2.

The installation 800 comprises an oven 802, filled with a liquid 850,configured to heat the cell to a treatment temperature greater than orequal to the melting temperature of the solid metallic lithium presentin the cells, for example 180.5° C. or 181° C. In the embodimentpresented, the liquid 850 is heated by the oven 802, and transfers heatto the assembly of cell(s).

The installation 800 comprises a pair of jaws 804 for holding the cell100, or the cell assembly 200, in a vertical, or at least inclined,position in which the first edge 110 is positioned above the level ofthe second edge 112. Each jaw 804 is mounted mobile on a vertical rail806 so as to displace the cell 100, or the assembly of cells 200,vertically.

The liquid 850 completely covers the assembly of cell(s), so that thefirst edge 110 is situated below the level of the liquid 850.

The installation 800 also comprises a pair of rollers 808, havingbetween them a gap corresponding to the thickness of the cell 100, or ofthe assembly of cells 200, minus the thickness of the solid layer orlayers of metallic lithium. The pair of rollers is positioned so thatwhen the jaws 804 are displaced upwards, the cell 100, respectively theassembly of cell(s) 200, passes between the rollers 808, starting fromthe second edge 112. Thus, the rollers apply a compression to the cell100, respectively to the cell assembly 200 progressively, starting fromthe second edge 112 and moving towards the first edge 110.

Of course, the invention is not limited to the examples detailed above.

For example, the composition of the electric battery cell comprisingsolid metallic lithium can be different to that indicated in FIG. 1.

In addition, the installation according to the invention can comprisedevices other than those shown in FIGS. 5 and 7, such as for examplemeans for cutting off the electrical connectors from the cell, means forcutting off excesses on one, or each, of the edges.

For example, the jaws, respectively 504 and 804, can be fixed, and it isthe rollers, respectively 508 and 808, that can be mobile and cancompress the assembly of cell(s) from the top down, respectively fromthe bottom up, according to the embodiment.

In addition, it is possible to use a single oven and several pairs ofrollers dedicated to one cell or an assembly of cells.

A pair of rollers can operate in order to simultaneously treat severaladjacent assemblies of cell(s).

By way of example, the step 609 can be carried out by submerging thecell 100 or the assembly of cell(s) 200 in the liquid 850, or by fillingthe oven 802 with the liquid 850, so that the liquid 850 covers theassembly of cell(s) 200, respectively the cell 100.

It should be noted that the orientation of the first edge 110 of theassembly, from which extend(s) one or more negative electrode orelectrodes 102, is a function of the density of the fluid in which thecell 100, or the assembly 200 of cells, is immersed. In the event thatthe fluid is a gas, which is covered by the first solution proposed bythe present invention, then the first edge 110 will be situated belowthe second edge 112 from which extend(s) one or more positive electrodeor electrodes 104, since the gas has a lower density than the lithium.In the event that the fluid is a liquid denser than the lithium, whichis covered by the second solution proposed by the present invention,then the first edge 110 will be situated above the second edge 112.

In the event that the fluid is a liquid less dense than the lithium,then the orientation of the first edge 110 will be below the second edge112, as shown in the first embodiment.

In addition, the direction of compression of the cell 100, by therollers 508, respectively 808, is more advantageous for compressing thecell from the second edge 112 to the first edge 110. Thus according tothe density of the fluid, the direction of compression is not identical,as can be seen in the examples shown in FIGS. 5 and 8.

The first edge 110 can be characterized by the fact that it defines theside via which the lithium must flow, once it is in the liquid state.

1. A method for the extraction of lithium from an assembly of at leastone cell of an electric battery including solid metallic lithium, suchas a Lithium-Metal-Polymer battery, said method having an extractionphase comprising the following steps: positioning said assembly in anorientation in which a first edge of said assembly from which extend(s)one or more negative electrode or electrodes is located below a secondedge of said assembly, opposite said first edge, and from whichextend(s) one or more positive electrode(s); and heating said assemblyto a temperature, called treatment temperature, greater than or equal tothe melting temperature of said solid metallic lithium.
 2. The methodaccording to claim 1, characterized in that the positioning step carriesout a vertical positioning of the assembly of cell(s), in which thefirst edge is located downwards.
 3. The method according to claim 1,characterized in that the step of heating the assembly of cell(s) iscarried out under inert gas.
 4. The method according to claim 1,characterized in that the step of heating the assembly of cell(s) iscarried out under vacuum.
 5. The method according to claim 1,characterized in that it also comprises, before the extraction phase, astep of electrical charging of the assembly of cell(s), said extractionphase being applied to said charged assembly.
 6. The method according toclaim 1, characterized in that the extraction phase also comprises astep of compression of the assembly of cell(s).
 7. The method accordingto claim 6, characterized in that the compression step applies acompression to the surface of the assembly by sweeping the surface ofthe assembly from the second edge to the first edge.
 8. The methodaccording to claim 1, characterized in that it comprises, before theextraction phase, a step of removal of at least one electrical connectorfrom at least one cell.
 9. An installation for the extraction of lithiumfrom an assembly of at least one cell of an electric battery includingsolid metallic lithium, such as a Lithium-Metal-Polymer battery, saidinstallation comprising: a means for positioning said assembly in anorientation in which a first edge of said assembly from which extend(s)one or more negative electrode or electrodes is located below a secondedge of said assembly, opposite said first edge, and from whichextend(s) one or more positive electrode or electrodes; and heatingmeans configured to heat said assembly to a treatment temperaturegreater than or equal to the melting temperature of said solid metalliclithium.
 10. The installation according to claim 9, characterized inthat the heating means comprises an oven filled with inert gas.
 11. Theinstallation according claim 9, characterized in that it comprises acompression means of the assembly of cell(s).
 12. The installationaccording to claim 11, characterized in that the compression meanscomprises two rollers between which the assembly of cell(s) is passed.